Besides the common predators like big
sharks and occasionally killer whales, humans are the top
dolphin killers.
The human activities that kill dolphins are tuna fishing
because dolphins get trapped in the nets while they try to
pursuit tuna too.
Also, human pollution is a huge threat for dolphins causing
them to choke by eating waste or by damaging their senses and
making them easy prey for sharks.
The intense noise caused by human activities has been
catalogued as a threat for dolphins, as it has been proved that
noise can kill dolphins or at least confuse them.